Over the last few months, we’ve heard a lot about the MTA’s efforts at securing its system. A ongoing lawsuit against Lockheed Martin has left the current state of subway security in disarray, and approximately half of the system’s 4300 cameras do not work properly. Had everything gone according to plan, by now, the entire subway system would have been outfitted with closed-circuit security cameras.

Generally, this halting attempt at installing cameras doesn’t impact the public. We’ll ride the trains no matter what and hope for the best. But this weekend, two stories highlight both the benefits and limitations of subway security cameras. The first happened right here in New York when a stabbing on Sunday morning left two riders dead and the cops on the hunt for a killer. The NYPD’s efforts have been slowed by the lack of adequate security measures underground.

As Ray Rivera and Michael Grynbaum write in The Times today, Christopher St. — the station through which the alleged perp escaped — has no cameras, and overall, the system’s video surveillance system “remains a patchwork of lifeless cameras, unequipped stations and problem-plagued wiring.”

MTA and New York City officials are aware of the system’s shortcomings. “This definitely should have been recorded on surveillance camera,” Norman Seabrook, head of the MTA’s security committee, said to The Times “Post-9/11, the terrorist bombings that just occurred in Moscow, the two murders that just occurred plus other incidents that continue to occur in the subway system, we cannot wait any longer to ensure the safety of the public.”

Yet, the Moscow bombings, despite Seabrook’s concern, highlight just how useless security cameras can be. During the Monday morning rush hour, two suicide bombers detonated explosives in the Moscow Metro. The bombers are suspected to be a part of some Northern Caucasus separatist groups, and the blasts raised fears through Russia and the rest of the world.

In New York, the NYPD rushed to “activate” a security plan, Reuters reported on Monday. Police details flooded the subway system, and squads were dispatched to major transit hubs around the city. Although there was no suspected link between America’s enemies and the Russian attackers, the city wanted to maintain a strong security footing. It was, MTA spokesman Jeremy Soffin said to amNew York, a “precaution.”

Yet, I wonder if this response is more an example of wishful thinking and the limitations we run up against in defending an open and porous subway system than it is of precaution. By dispatching police after the fact, it is as though security officials are trying to close the barn door after the horse escaped. As former NYPD commissioner Howard Safir said to Heather Haddon, “There are so many entrances, so many stations, so many people. It’s virtually impossible to guarantee that it won’t be vulnerable.”

So where then does that leave New Yorkers on a daily basis? On the one hand, a killer is still at large because he was able to slip out of an unsecured subway system after stabbing two or three men on a subway train car that is surveillance-free. On the other, we are aware of the security risks we face as we ride the trains and now that, while exceedingly rare, a terrorist attack underground can be a devastating and tragic event. As station agents vanish and security dollars languish, the MTA must do what it can to guard against both kinds of subway attacks.

As Saturday night turned into Sunday morning, two men were fatally stabbed on a Brooklyn-bound 2 train. What happened on the train remains something of a mystery, but as more information comes to light, the tale is a particularly grisly one.

I first saw the news in The Times on Sunday morning when it was nothing more than a short report from the Associated Press. By the evening, their reporting had turned into a longer story with some details. Two groups of young men boarded the Brooklyn-bound 2 train making local stops. The first got on at 42nd St; the second got off later.

Somewhere in between 14th St. and Christopher St., Darnell Morel and Ricardo Williams were stabbed multiple times, and police stopped the train at Houston St. The assailants fled, and the two victims were both pronounced dead on arrival at St. Vincent. A third stabbing victim, says the report, remains in stable condition at the hospital.

The Daily News and The Post provided different takes on the story with the help of the victims’ friends. Apparently, ten friends were on the way back from a night out at the Cellar Bar in the Bryant Park Hotel. At 14th St., one of the group threw a bag of garbage out of the train car and hit another passenger on the platform. He and his three friends got agitated and pulled a knife. As the group tried to calm down the potential assailant, Morel and Williams were stabbed. “When we left, he stood banging on the glass with the knife in his hand,” Bryan Woods, a friend of the two victims, said to The Daily News. “[He was] laughing like he knew he got one of us.”

Cops are still looking for alleged attackers and are trying to piece together a more complete story. Both Morel and Williams, reported The Times, had arrest records. For the papers, this is a story of the city’s increased homicide rate. The subways, relatively crime-free for years, haven’t seen a spike in petty crime, but across the city, the murder rate has been climbing. Is it, as some bemoan, a return to the 1980s? “I feel like the city is losing its grip,” Liz McCarvill, a West Village resident, said to The Post. “I have to take the subway at 4:30 in the morning to get to the airport. It’ll be me and the people who kill each other.”

That is, I think, an overstatement borne out of fear when someone is attacked and murdered on your train. I ride the 2 train regularly, and I knkow McCarvill’s concerns. Still, what happened yesterday morning is similar to the murder that took place on the D train in November. There, one rider refused to remove his bags from a seat for another rider, and that other rider killed his co-straphanger over a seat. The lessons I offered up in November served as a reminder to be wary of those around you on the train. Most New Yorkers are calm and collected; they won’t snap at an obvious mistake. But the one guy out of 100 who does can mean harm.

I want to know more about this garbage bag that was tossed from a train and the reaction of the alleged killers to that bag. The subways and streets of new york City are safe, but sometimes safety can lead to complacency. A tragedy on the 2 train yesterday didn’t need to happen.